Agrochemical compositions have been used to improve the quality and quantity of farm grown products. In this regard they can enhance biological activity and act as nutrients, growth regulators and/or pesticides, for instance as herbicides, insecticides, fungicides, or acaricides. However, since they are expensive to make and purchase, it is desirable to reduce their overall cost in use by improving their effectiveness in a unit area treated with the agrochemical.
In order to improve or enhance the effectiveness of many agrochemicals, certain materials are added to water-based agricultural spray mixtures containing the agrochemical and concurrently applied to agricultural substrates. These materials are commonly identified as agricultural spray adjuvants and exist in a wide variety of forms and compositions that are used today in commercial agriculture. These adjuvant products are used to provide a broad array of effects in typical use including, but not limited to, foam control, enhancement of the effectiveness of a specific agrochemical, and/or modification of the agricultural spray mixture for either improved stability or modulation of spray droplet diameter.
In the United States, most economically advantageous adjuvant products used to improve or enhance the efficacy of an agrochemical, primarily a pesticide, are supplied as liquids. The preferred liquid adjuvant products (for both convenience and economy) manufactured and sold in the US are supplied as concentrated liquids and fall into two primary categories. These categories are: (1) self-emulsifying oil and surfactant compositions more commonly identified as Crop Oil Concentrates (COC), and (2) readily water soluble or dispersible surfactant formulations known as concentrated liquid Non-Ionic Surfactants (NIS). Commercial distribution channels in the US efficiently transport large volumes of such products, primarily in bulk form, making COC and NIS type products very economical for their intended use. By improving the efficacy of the more costly pesticide through its combination in spray mixtures with an economically advantageous, primarily low cost, adjuvant product, the overall economics of commercial agriculture can be improved. Use of effective adjuvant products in this manner decreases the seasonal cost to produce agricultural commodities and may also improve commodity yields, offering economic benefits to those who use them.
One of the largest single groups of such effective liquid adjuvant products sold in the United States (by volume) is a COC composition containing between 60 and 90% of a suitable agricultural grade of mineral oil; an alternate form of this adjuvant type contains a vegetable oil or methylated seed oil. All commercially significant forms of this adjuvant type commonly contain an oil soluble emulsifier composition composed of a blend of anionic and/or non-ionic surfactants that provides self-emulsification of the oil component upon dilution in a water-based agricultural spray mixture; the total surfactant concentration in a typical COC product can range from 1 to 40%, most typically between 10 and 17%.
While the oil and surfactant composition in a COC adjuvant product could also be offered as a pre-emulsified system in water (an oil-in-water emulsion), the added cost of production for an emulsified adjuvant product tends to make it less economically advantageous than the equivalent volume of oil adjuvant offered as a COC. Water based systems also have the undesirable characteristics of being generally more complicated to develop and manufacture and of requiring the use of discrete thickening, preserving, and anti-freeze systems due to the tendency of water based emulsions to support microbial growth, cream or settle/sediment, and deteriorate over time or during the freeze-thaw cycle. The effect of including water as the dispersing medium also dilutes the active components (oil and surfactant composition) making the system more expensive to deliver in the field on a pound of “active” adjuvant basis. Logistics costs also increase on this basis as more water is shipped than may otherwise be present in a comparable COC type system.
In recent times, there have been specific improvements upon the cost-effectiveness of the described economically advantageous crop oil concentrates. Most of these improvements have focused on two aspects of the composition. The first aspect is increasing the total concentration of oil soluble surfactant emulsifier which has resulted in a change in preferred surfactant concentration from 12-17% ten years ago to approximately 40% at the current time; this change was associated with a reduction in the amount of COC adjuvant product applied per unit area and resulted in improved cost-in-use attributes for the adjuvant. The second aspect is the selection of specific surfactant types based on both field data and scientific judgement; this change was associated with improved performance of the adjuvant product with specific pesticide products. PCT Publication WO 95 03881 by Auda et al describes an agrochemical crop oil concentrate containing an oil or oils, hydrocarbyl saccharide surfactant, and additional non-ionic surfactant that emulsifies readily upon dilution in water. This COC adjuvant composition was associated with enhancement or improvement of weed control performance in conjunction with with soluble salts of N-phosphonomethylglycine.
More recently, U.S. Pat. No. 5,945,377 to Penner describes compositions incorporating a postemergence herbicide and a monosaccharide, particularly fructose, as a potentiator of the herbicide against weeds without decreasing tolerance of a crop plant to the herbicide. The compositions are used as a spray in water in a method for killing weeds. Although not considered an NIS adjuvant, corn syrup was evaluated as an adjuvant with several postemergence herbicides in the greenhouse and field studies. The greatest enhancement of herbicide activity was observed with high fructose corn syrup applied in combination with an ammonium sulfate and an effective non-ionic adjuvant with anionic herbicides such as glyphosate and glufosinate for control of grass species such as giant foxtail. The efficacy of the corn syrup as an adjuvant was both weed and herbicide specific.
The previously mentioned publication (WO 95 03881) describes self-dispersing alkylpolysaccharide surfactants in crop oil concentrates (COC's). These compositions did not include additional aqueous liquid non-surfactant polysaccharide components which have been found recently to promote the herbicidal activity of glyphosate. It was concluded that a robust, single phase composition containing: (1) an oil adjuvant, (2) a saccharide adjuvant, and (3) an optimal amount of surfactant with a corresponding minimum of additional water could allow the delivery of a highly concentrated liquid agricultural adjuvant product with a total surfactant concentration similar to those in use today (ca. 10-40% w/w). The successful incorporation of the inexpensive and efficacious saccharide adjuvant would improve the cost-effectiveness of the finished adjuvant product. The resulting product is commercially advantageous for the manufacturer and economically beneficial to the purchaser/user. An additional advantage for combining the saccharide and surfactant adjuvant composition with the traditional COC adjuvant composition would be the significant commercial advantage obtained by being able to provide one very broadly effective adjuvant composition having the preferred characteristics of the COC, NIS, and newer saccharide adjuvant types.
The compositions described are intended as commercial alternatives to traditional 17 and 40% surfactant in oil based COC adjuvants used in the agricultural market. These COC adjuvant types, although cost-effective for use with most water-dipsersible agrochemicals, are not the most effective type of adjuvant for the soluble salts of N-phosphonomethylglycine, most commonly called glyphosate, which represents the largest commercial pesticide sold in the US and as a result presents the largest single adjuvant sales opportunity. The most efficacious NIS adjuvants for use with glyphosate, identified as ethoxylated tallow alkylamines, are for the current time typically combined into concentrated glyposate solution products and are therefore not readily accessible to adjuvant products intended for combination into agricultural spray mixtures. With the expiration of patents on concentrated glyphosate salt solution products, other forms of the pesticide, including products which intentionally do not include the preferred NIS adjuvant as a means to reduce the cost of formulated glyphosate and increase its concentration in solution products may also become available. It would be advantageous to alter the traditional COC product or the COC product described in WO 95 03881 to demonstrate improved efficacy enhancement with glyphosate products; this would be highly desireable as a means of expanding the market for the highly cost-effective COC adjuvant product.
Ideally it is desireable to achieve a surfactant composition that serves as both the combined COC adjuvant self-emulsifier and compatibilizer/stabilizer for the saccharide component and which also has the ability to stabilize and self-emulsify the oil alone (without the saccharide component) as well as having special advantages in that it offers improved economies in the purchase of a single surfactant composition and in enabling the flexible manufacturing of COC adjuvants in the same surfactant composition both with and without added liquid saccharide components. Since the corn syrup adjuvant also requires concurrent application of a nonionic surfactant adjuvant for optimum performance, the direct combination of the oil and corn syrup with a single surfactant system that would both “activate” the saccharide and concurrently emulsify the oil component would have the greatest economic and competitive advantage. Essentially, by using the combined COC and saccharide NIS product concept, the composition would be 100% active with a minimum total concentration of the surfactant composition required for optimum performance. Since the surfactant constitutes the most costly input for manufacturing on a component purchased price (per pound) basis, reducing surfactant to the minimum required for optimal activity is highly desireable.
The greatest difficulty in developing the combined saccharide COC adjuvant product is the identification of suitable surfactant systems which would enable the formulation of homogeneous compositions that would function both as robust stabilizers for a highly concentrated liquid saccharide solution in an oil adjuvant and which would provide the self-emulsification upon dilution that is required. These two opposing effects must be delivered in one adjuvant product with a minimum of total surfactant. Preferably a foam control agent would also be included in the composition.
In U.S. Pat. No. 5,885,646 to Wong, there is described a process for preparing nut spreads having a sugar level of from about 15 to about 50% and especially flavored nut spreads having such relatively high levels of sugar. A substantially homogeneous blend is prepared from a fluid suspension consisting essentially of an intimate mixture of sugar, liquid oil and lecithin as a surfactant to improve the fluidity of the suspension, a nut solids-containing mixture and a flavorant that is preferably added to the fluid suspension. The resulting flavored nut spreads are more fluid and softer than products made without using the fluid suspension. This invention does not provide for the characteristics of either liquid product homogeneity or self-emulsification and demonstrates a relatively high viscosity, which makes it irrelevant to this invention.
In U.S. Pat. No. 3,959,498 to Lyall there is described a one step process for applying sugar and an edible fat or oil to cereal bases. No separate step of spraying the oil into the cereal substrate is necessary. The invention also provides an emulsion cereal coating for achieving the above purpose, and a method of preparing said coating. A quantity of edible fats or oils or other edible oil- or fat-derived oleaginous material (5-32%) along with a quantity of emulsifier (0.5-5%) is added to an aqueous sugar solution (60-85% solids) to make up a syrup emulsion having a water content in the range of 9%-34% by weight. The edible fat or oil and emulsifier are added to the aqueous syrup at a temperature ranging from 115° F., to 155° F. (46.1° C. to 68.3° C., and after emulsification, the mixture is heated to about 180° F. (82.2° C.). As in the above example, this invention does not provide for the characteristics of either liquid product homogeneity or self-emulsification and demonstrates a relatively high viscosity, which makes it inapplicable to this invention. In addition it provides for an oil-in-water emulsion whereas the composition claimed herein is a liquid homogeneous (solution or microemulsion) product.